Field of the Invention
In one aspect of the present invention, an immunogenic composition effective for inducing an immune response against infection by Mycoplasma hyopneumoniae (M. hyo) is provided. More particularly, the present invention is concerned with an immunogenic composition effective for inducing, eliciting, or providing an immune response that protects an animal receiving such a composition and reduces the incidence of, or lessens the severity of, the clinical symptoms associated with M. hyo infection. Still more particularly, the present invention is concerned with an immunogenic composition that includes therein cell-based antigen, preferably a bacterin, which confers a protective immune response against infection by M. hyo. Even more particularly, the present invention is concerned with an immunogenic composition comprising M. hyo bacterin, wherein administration of the bacterin results in a protective immune response against infection by M. hyo. Most particularly, the present invention is concerned with an immunogenic composition effective for conferring a protective immune response to a swine receiving the immunogenic composition, and wherein a dose of the composition comprises M. hyo bacterin with a relative potency (RP) of at least 1.22. Additionally, methods for producing and administering such immunogenic compositions are provided.
In another aspect of the present invention, an immunogenic composition effective for inducing an immune response against infection by porcine circovirus 2 (PCV2) is provided. More particularly, the present invention is concerned with an immunogenic composition effective for providing an immune response that protects an animal receiving the composition by reducing the incidence of, or lessening the severity of the clinical symptoms associated with PCV2 infection. Still more particularly, the present invention is concerned with a protein-based immunogenic composition that confers a protective immune response against infection by PCV2. Even more particularly, the present invention is concerned with an immunogenic composition comprising ORF2 of PCV2, wherein administration of PCV2-ORF2 results in a protective immune response against infection by PCV2. Most particularly, the present invention is concerned with an immunogenic composition effective for conferring a protective immune response to a swine receiving the immunogenic composition, and wherein the composition comprises the protein expressed by ORF2 of PCV2 and has an RP value of at least 1.38. Additionally, the present invention provides methods for producing and administering such immunogenic compositions.
In another aspect of the present invention, a combination immunogenic composition, combination vaccine, or multivalent immunogenic composition or vaccine is provided. More particularly, the present invention provides immunogenic compositions effective at inducing an immune response against infection by M. hyo and at least one other disease-causing organism for swine. Even more particularly, the present invention provides a composition effective at inducing an immune response against infection by M. hyo and inducing an immune response against infection by PCV2. Preferably, the immune response against M. hyo and PCV2 is sufficient to reduce the severity of or incidence of clinical signs or symptoms associated with each respective pathogen up to and including preventing the same. In preferred forms of such an immunogenic composition, the M. hyo portion thereof will have an RP value of at least 1.22 and the PCV2 portion thereof will also have an RP value of at least 1.38. The present invention further provides methods of producing and administering such compositions.
Description of the Prior Art
Mycoplasma hyopneumoniae is a small bacterium (400-1200 nm) classified in the mycoplasmataceae family. M. hyo is associated with Enzootic Pneumonia, a swine respiratory disease commonly seen in growing and finishing pigs. M. hyo attacks the cilia of epithelial cells of the windpipe and lungs, causing the cilia to stop beating (ciliostasis) and eventually causing areas of the lungs to collapse. Depending on the extent of the disease, daily live weight gain of infected swine can be reduced by up to 17%. Enzootic Pneumonia is widespread in swine populations and present in almost every swine herd. M. hyo is considered to be a primary pathogen that facilitates entry of PRRSV and other respiratory pathogens into the lungs. Three separate strains, 232, J, & 7448, have had their genomes sequenced (Minion et al., J. Bacteriol. 186: 7123-33, 2004; Vasconcelos et al., J. Bacteriol. 187: 5568-77, 2005). Clinical signs of M. hyo infection include a dry cough, impaired performance, and lung lesions.
Porcine circovirus type 2 (PCV2) is a small (17-22 nm in diameter), icosahedral, non-enveloped DNA virus, which contains a single-stranded circular genome. PCV2 shares approximately 80% sequence identity with porcine circovirus type 1 (PCV1). However, in contrast with PCV1, which is generally non-virulent, swine infected with PCV2 exhibit a syndrome commonly referred to as Post-weaning Multisystemic Wasting Syndrome (PMWS). PMWS is clinically characterized by wasting, paleness of the skin, unthriftiness, respiratory distress, diarrhea, icterus, and jaundice. In some affected swine, a combination of all symptoms will be apparent while other swine will only have one or two of these symptoms. During necropsy, microscopic and macroscopic lesions also appear on multiple tissues and organs, with lymphoid organs being the most common site for lesions. A strong correlation has been observed between the amount of PCV2 nucleic acid or antigen and the severity of microscopic lymphoid lesions. Mortality rates for swine infected with PCV2 can approach 80%. In addition to PMWS, PCV2 has been associated with several other infections including pseudorabies, porcine reproductive and respiratory syndrome (PRRS), Glasser's disease, streptococcal meningitis, salmonellosis, postweaning colibacillosis, dietetic hepatosis, and suppurative bronchopneumonia.
Open reading frame 2 (ORF2) protein of PCV2, having an approximate molecular weight of 30 kDa when run on SDS-PAGE gel, has been utilized in the past as an antigenic component in vaccines for PCV2. Typical methods of obtaining ORF2 for use in such vaccines generally consist of amplifying the PCV2 DNA coding for ORF2, transfecting a viral vector with the ORF2 DNA, infecting cells with the viral vector containing the ORF2 DNA, permitting the virus to express ORF2 protein within the cell, and extracting the ORF2 protein from the cell via cell lysis. These procedures generally take up to about four days after infection of the cells by the viral vector. However, these procedures have a disadvantage in that the extraction procedures are both costly and time-consuming. Additionally, the amount of ORF2 recovered from the cells is not very high; consequently, a large number of cells need to be infected by a large number of viral vectors in order to obtain sufficient quantities of the recombinant expressed protein for use in vaccines and the like.
Accordingly, what is needed in the art is an immunogenic composition that confers a protective immune response against, reduces the incidence of, and/or lessens the severity of or prevents the clinical signs associated with PCV2 infection and M. hyo infection. In particular, what is needed in the art is a combination vaccine comprising M. hyo antigen and PCV-2 antigen in sufficient amounts to confer a protective immune response against, reduces the incidence of, and/or lessens the severity of or prevents the clinical signs associated with PCV2 infection and M. hyo infection after a single administration of such vaccine. Such a vaccine would improve the compliance of swine vaccines.